<?php

namespace App\Support;

final class CrmPrefillCodec
{
    /** @return array<string, mixed>|null */
    public static function decode(?string $token): ?array
    {
        if (! is_string($token) || $token === '') {
            return null;
        }

        $padded = $token.str_repeat('=', (4 - strlen($token) % 4) % 4);
        $json = base64_decode(strtr($padded, '-_', '+/'), true);

        if ($json === false) {
            return null;
        }

        try {
            $data = json_decode($json, true, 512, JSON_THROW_ON_ERROR);
        } catch (\JsonException) {
            return null;
        }

        return is_array($data) ? $data : null;
    }
}